Setup a thick VNET jail for torrenting on FreeBSD

Setup the VNET bridge

Create the bridge.

ifconfig bridge create

Attach the bridge to the main network interface. igc0 in this case. For some reason, the resulting bridge device is named igb0bridge, rather than bridge0.

ifconfig igb0bridge addm igc0

To make this persistent across reboots, add the following to /etc/rc.conf.

defaultrouter="10.0.0.1"
cloned_interfaces="igb0bridge"
ifconfig_igc0bridge="inet 10.0.0.8/24 addm igc0 up"

Create the classic (thick) jail

Create the ZFS datasets for the jails. We'll use basejail as a template for subsequent jails.

zfs create -o mountpoint=/jails naspool/jails
zfs create naspool/jails/basejail

Use the bsdinstall utility to bootstrap the base system to the basejail.

export DISTRIBUTIONS="base.txz"
export BSDINSTALL_DISTSITE=https://download.freebsd.org/ftp/releases/amd64/14.2-RELEASE/
bsdinstall jail /jails/basejail

Run freebsd-update to update the base jail.

freebsd-update -b /jails/basejail fetch install
freebsd-update -b /jails/basejail IDS

We now snapshot the basejail and create a clone of this snapshot for the torrenting jail that we will use for Anna's Archive.

zfs snapshot naspool/jails/basejail@`freebsd-version`
zfs clone naspool/jails/basejail@`freebsd-version` naspool/jails/torrenting

We now use the following configuration for /etc/jail.conf.

torrenting {
exec.consolelog = "/var/log/jail_console_${name}.log";
allow.raw_sockets;
exec.clean;
mount.devfs;
devfs_ruleset = 11;
path = "/jails/${name}";
host.hostname = "${name}";
vnet;
vnet.interface = "${epair}b";
$id = "127";
$ip = "10.0.0.${id}/24";
$gateway = "10.0.0.1";
$bridge = "igb0bridge";
$epair = "epair${id}";

exec.prestart = "/sbin/ifconfig ${epair} create up";
exec.prestart += "/sbin/ifconfig ${epair}a up descr jail:${name}";
exec.prestart += "/sbin/ifconfig ${bridge} addm ${epair}a up";
exec.start += "/sbin/ifconfig ${epair}b ${ip} up";
exec.start += "/sbin/route add default ${gateway}";
exec.start += "/bin/sh /etc/rc";
exec.stop = "/bin/sh /etc/rc.shutdown";
exec.poststop = "/sbin/ifconfig ${bridge} deletem ${epair}a";
exec.poststop += "/sbin/ifconfig ${epair}a destroy";
}

Now we create the devfs ruleset to enable access to devices under /dev inside the jail. Add the following to /etc/devfs.rules.

[devfsrules_jail_vnet=11]
add include $devfsrules_hide_all
add include $devfsrules_unhide_basic
add include $devfsrules_unhide_login
add include $devfsrules_jail
add path 'tun*' unhide
add path 'bpf*' unhide

Enable the jail utility in /etc/rc.conf.

sysrc jail_enable="YES"
sysrc jail_parallel_start="YES"

Start the jail service for torrenting jail.

service jail start torrenting

Setting up Wireguard inside the jail

Since we have the /dev/tun* devfs rule, we now need to install Wireguard inside the jail.

jexec -u root torrenting

pkg install wireguard-tools wireguard-go

Download a Wireguard configuration for ProtonVPN, and save it to /usr/local/etc/wireguard/wg0.conf.

Enable Wireguard to run when the jail boots up.

sysrc wireguard_enable="YES"
sysrc wireguard_interfaces="wg0"

Start the Wireguard daemon and make sure you are connected to it properly.

service wireguard start

curl ipinfo.io

The curl command should display the IP address of the Wireguard server defined in /usr/local/etc/wireguard/wg0.conf.

Setting up qBittorrent inside the jail

Install the qbittorrent-nox package.

pkg install -y qbittorrent-nox

Before running the daemon from /usr/local/etc/rc.d/qbittorrent, we must run the qbittorrent command from the shell so that we can see the default password generated for the web UI. For some reason it is not shown in any logs, and the qbittorrent nox manpage wrongly says the password is "adminadmin".

pkg install -y sudo
sudo -u qbittorrent qbittorrent-nox --profile=/var/db/qbittorrent/conf --save-path=/var/db/qbittorrent/Downloads --confirm-legal-notice

Copy the password displayed after running the command. Login to the qBittorrent web UI at http://10.0.0.127:8080 with login admin and the password you copied. In the web UI, open the options menu and go over to the Web UI tab. Change the login password to your own. Save the options to close the menu.

Now press CTRL-c to stop the qbittorrent-nox process. Make the following changes to the torrenting jail's /etc/rc.conf.

sysrc qbittorrent_enable="YES"
sysrc qbittorrent_flags="--confirm-legal-notice"

Enable the qBittorrent daemon.

service qbittorrent start

Go back to the web UI at http://10.0.0.127:8080 . Go to the options menu and go over to the Advanced tab, which is the very last tab. Change the network interface to wg0.

Finding the forwarded port that the ProtonVPN server is using

Install the libnatpmp package.

Make sure that port forwarding is allowed on the server you're connected to, which it should be if you enabled it while creating the Wireguard configuration on the ProtonVPN website. Run the natpmpc command against the ProtonVPN Wireguard gateway.

natpmpc -g 10.2.0.1

If the output looks like the following, you're good.

initnatpmp() returned 0 (SUCCESS)
using gateway : 10.2.0.1
sendpublicaddressrequest returned 2 (SUCCESS)
readnatpmpresponseorretry returned 0 (OK)
Public IP address : 62.112.9.165
epoch = 58081
closenatpmp() returned 0 (SUCCESS)

Now create the UDP and TCP port mappings, then loop natpmpc so that it doesn't expire.

while true ; do date ; natpmpc -a 1 0 udp 60 -g 10.2.0.1 && natpmpc -a 1 0 tcp 60 -g 10.2.0.1 || { echo -e "ERROR with natpmpc command \a" ; break ; } ; sleep 45 ; done

The port allocated for this server is shown on the line that says "Mapped public port XXXXX protocol UDP to local port 0 lifetime 60". Port forwarding is now activated. Copy this port number and, in the qBittorrent web UI options menu, go to the Connections tab and enter it into the "Port used for incoming connections" box. Make sure to uncheck the "Use UPnP/NAT-PMP port forwarding from my router" box.

If the loop terminates, you'll need to re-run this loop script each time you start a new port forwarding session or the port will only stay open for 60 seconds.

P2P NAT port forwarding script with supervisord

Install supervisord.

sudo pkg install -y py311-supervisor

Enable the supervisord service.

sudo sysrc supervisord_enable="YES"

Edit /usr/local/etc/supervisord.conf, and add the following to the bottom of the file.

[program:natpmpcd]
command=/usr/local/bin/natpmpcd
autostart=true

Add the following contents to a file at /usr/local/bin/natpmpcd.

#!/bin/sh

port=$(/usr/local/bin/natpmpc -a 1 0 udp 60 -g 10.2.0.1 | grep "Mapped public port" | awk '{print $4}')
echo $port | tee /usr/local/etc/natvpn_port.txt

while true; do
date
if ! /usr/local/bin/natpmpc -a 1 0 udp 60 -g 10.2.0.1 && /usr/local/bin/natpmpc -a 1 0 tcp 60 -g 10.2.0.1; then
echo "error Failure natpmpc $(date)"
break
fi
sleep 45
done

Ensure the script is executable with chmod +x /usr/local/bin/natpmpcd.

supervisord will start the above shell script automatically. Ensure supervisord service is started.

sudo service supervisord start

The script will print out the forwarded port number at /usr/local/etc/natvpn_port.txt.

cat /usr/local/etc/natvpn_port.txt
48565